Papillomavirus infect ions may contribute to the pathogenesis of cancer of the cervix, vulva, penis, and skin. Since immune deficient patients are at greater risk than immune competent patients, it is likely that immunity can interfere with the role of the papillomavirus. Theoretically immunity can intervene at three points in the pathogenesis: the initial infection, during the lesion growth phase, and during the malignant transformation. The Shope papilloma/carcinoma complex of rabbits will be used as a model system to study mechanisms of intervention. Specifically, we will l)define the nature of the components of the conformational neutralizing epitopes on papillomavirus lesions; and to 2)compare the T-cell immune response to papillomavirus- infected cells in papilloma regressor and progressor rabbits.